BMW Z4 Tires and Wheels

Comments

Thanks for sharing your views about my steering problem. In almost every other respect, I love my Z4. However I've had more than my share of problems. I'm on my third manual transmission--the first two frequently got so stuck in 6th gear I had to pull over, stop and use both hands to get the transmission into neutral! I'm also on my second radio--the first one would light up but no sound would come forth.

I wish I could agree with you about the steering. But I'd rather have predictable steering than a car that tramlines with every defect in the road. As far as I'm concerned, this is a serious safety issue. If I can't get it resolved fairly soon with new tires, this baby is going bye-bye! Why would I want to take tight corners at high speed if I end up hitting the curb or another car!

I just joined this forum on the advice of a friend who owns an import repair shop. I purchased a 2005 Z-4 (probably the last "boy toy" my wife will let me have) and I just love it!!! It has every option available for this year to include the premium sport package. It rides firmer than I am accustomed-not like say; a TR-6 I had some time ago. Yes, I am a senior citizen (South of 64 yrs.) so, the question becomes what can I replace the original RFT's with to increase ride comfort to the maximum? My Z-4 has about 40k + miles and the only thing my guy tells me after he went through it before I bought it is: oil change, possibly some brake work, rotate/balance tires. All of this: "sometime this year." The tires look very good but I am told after a certain amount of time, one should consider replacement. What is available, run flat or other wise, that I should consider to get the smoothest ride?Thanks,Cliff

I asked a lot of questions and did a bunch of reading over a 6-month period because I could not get answers from BMW. I finally replaced the OEM tires with the same brand/model but in a newer design about a month ago. My Z4 runs a little smoother but it still does not handle the gaps and seams in the road as easily as I would like. OEM tires were Bridgestone Potenza 225/45 R17. The new tires are exactly the same except they're Generation II. BMW is putting Gen III tires on the new Z4's but said they were unable to get those shipped to the dealership yet as replacements. That may change by summer.

In the meantime, you may want to consider a non-runflat tire option. One tire dealer recommended that route if I wanted a really smooth ride. The downside is that you need to carry a can of tire inflator plus some sealant or "slime" to enable you to get to a repair shop in the event of a flat.

If you'd like, I'd be happy to share the full text of an article by an auto writer about testing runflat tires on BMW's. It's pretty interesting background and provides a glimpse of the future of runflat tires.

Thanks Steve. I appreciate your prompt response. Of course I would be interested in you forwarding any info you have: (cliftonburris@att.net). After your comments, I checked my tires and they are; Bridgestone Pontenza 225/40 R18, 88W. It seems from your comments I also conclude that the "seams and gaps" are less than to be desired. I also attribute this to a minor difference between hydraualic as opposed to electric operated steering. Suffice to say, I am a person who loves to drive this car when it can be done safely--not at my expense or others. These times are rare in my area.Cliff

I assume from your note that you have hydraulic steering on your '06 Z4, is that correct? The electronic steering on my '07 Z4 may be a contributing factor to the tramlining I experience. BMW seems to be going electronic on many components to provide more feedback to the driver and more precise control. But as a real amateur about these things, that may also mean more feedback than I really want.

In response to my handling concerns, the dealer performed several alignment checks & adjustments. They also re-calibrated something called the steering angle sensor. Apparently this is another electronic device that constantly monitors the direction in which the front wheels are pointing. Again more feedback to the steering wheel.

I will send you a copy of the 3G runflat article directly to your email address along with a couple of additional comments so we can avoid doing all this sign-in stuff.

Have fun with your new toy, especially now that spring is here--at least it's supposed to be. We had a good shot of snow here in Denver two days ago but it may finally warm up enough this weekend to get our tomato plants in the ground!

Here's the article I found on the web that finally enabled me to convince my BMW dealer that newer runflat tires might help eliminate the tramlining problem I was having. It helped so much that between BMW and the dealer they picked up 2/3 of the cost of four new Bridgestone RunFlats for my car.

++++++++++++++++++++++++++++++++++++++++++++++++

Bridgestone 3G RFT Tires take the shock out of run-flats

by Michael Harley on Jul 6th 2009

Compared to a conventional tire, the construction of a self-supporting run-flat requires additional material thickness in the sidewalls to prevent the tire's collapse once it has lost pressure. It is this additional reinforcement that adds weight, reduces ride comfort, and increases rolling resistance (these characteristics are the kiss-of-death to performance).

Consumers embraced the additional mobility and safety benefits of the 2G RFT, but they never warmed to the handling compromises as a result of the additional unsprung weight, the harsh ride (the sidewalls are a noticeable 15 percent harder than a conventional tire, says Bridgestone), or the expensive replacement cost (up to 30 percent higher, in some cases). Frustrated, many vehicle owners exchanged their run-flat tires with conventional tires even before it was time for their replacement.

Bridgestone research and prowess resulted in three new cutting-edge technologies:Unique ply construction: The reinforcing layers of a tire are called the "ply." Bridgestone developed a tire ply that uses the heat generated by a deflated tire to contract and curb deformation. In simple terms, the material in the new sidewalls automatically shrinks to abate damage from abrasion and heat. When the tire cools, the ply automatically returns to its original state.

New rubber compounds: Laboratory-engineered rubber compounds, Bridgestone calls them "NanoPro-Tech," are also used in the sidewalls to limit heat. Conventional tire compounds warm through friction between the carbon and polymers (two common tire ingredients). By optimally distributing the polymers, friction and heat are minimized.

Innovative heat control: Bridgestone developed so-called "cooling fin" technology for the new tire. Molded into the sidewall are small protrusions (think of them as miniature spoilers). While this seems rather rudimentary, they effectively disrupt the airflow at the surface to help radiate heat and cool the tire.

Bridgestone encouraged us to try its new third-generation run-flat (3G RFT) from behind the wheel. Strapped in near identical late-model BMW 5 Series vehicles, Bridgestone offered us the opportunity to drive three variants of its high-performance RE050A tire: Conventional, 2G RFT, and 3G RFT.We drove the conventional RE050A first. A high-performance tire fitted to such cars as the Nissan 370Z and Lexus IS-F, the standard rubber was comfortable on the smooth sections. The course/rough pavements didn't provide much of a challenge either as the compliant sidewalls absorbed the abuse without drama.

Next, we tried a set of RE050A "2G" run-flats. While they were comfortable on the smooth sections, the compromises of the 2G run-flats were immediately evident when we entered the first sections of rough pavement. What had been damped by shock-absorbing sidewalls on the standard tires was now transferred into the cabin in the form of sharp, and rather uncomfortable, impacts. This test reinforced what many owners have expressed and what we have personally experienced.

The final run through the test course was done with the all-new RE050A "3G" run-flats. Eureka! Surprising even the skeptics among us, the third-generation tires were nearly imperceptible in ride quality from the standard tires (non run-flat) we had driven on merely minutes earlier. The ride was very comfortable. According to Bridgestone, test instruments reveal that the slight difference in ride quality was a near-imperceptible 5 percent change in harshness.

Another fleet of late-model BMW 5 Series vehicles were fitted with 2G RFT and 3G RFT tires for back-to-back comparisons. The roads were in fairly lousy condition, but they again demonstrated the newfound compliance one can expect with the third-generation run-flat.

The track sessions and test drives made it clear that Bridgestone has eliminated the biggest objection to run-flat tires &#150; abusive ride quality. We never had an opportunity to push the performance envelope of the tire, but Bridgestone says the tread compound of the RE050A 3G RFT is identical to that on the conventional tire, so the grip levels should be very high.

+++++++++++++++++++++++++++++++++++But wait, there's more to the story:

There are two "However's" and one "Therefore" to add to my post. However #1: The dealer could not get their hands on 3G RunFlats, even though the factory is currently delivering 2010 Z4's with them installed. So they installed 2G's all around on my Z4. However #2: The 2G's did not make a noticeable improvement in handling.

Therefore #1: After driving on the 2G's for a month and finding the Z4 still incredibly difficult to handle, I traded it in and bought a new Lexus IS 250C. After three very frustrating years of coping with "superior German engineering" that never translated into an enjoyable driving experience, I'm now a very happy man. Plus I now have two more seats, a slick convertible hardtop and a ton of goodies that actually make driving fun--for the about the same $$.

I have a 2007 BMW Z4. I wanted a six-speed so I got a 3.0i with the sports package. Probably should have done my homework a bit better. I bought the vehicle used (after having driven and loved my BMW Z3 for ten years and 130,000 miles). I was not aware that the car has different size tires on the front and the rear so they can't be rotated. I don't know what genius of German engineering decided this was a good idea. (Yea, I know it is about performance and handling, but practicality should enter into the equation somewhere.) Between the fact that the tires can't be rotated and the negative camber, the rear tires wear out in 10,000 miles, with more wear on the inside than the outside. It is my understanding that the inability to rotate them and the uneven wear voids any mileage warranties that come with the tires. I have received a suggestion to use Michelin Pilot Sport A4 Plus tires on it. However, if all of the tires are going to wear out in the same amount of time (and the warranty will not be valid) I would rather go with something cheaper. Any experiences or advice you can share?

As said before, while some sports cars and novelty cars were made with off size tires, it still doesn't dissuade me from my original premise, it is uncommon for standard production cars to be made with different sized front and rear tires.

Why? It costs more, it generally doesn't improve handling and it limits ones ability to "rotate" tires extending tread wear life. Does this stop car makers from doing it. No. Why? Because they think it may increase the look and appeal; hence, sales for certain sports-oriented car designs.

Speaking of the MR2, back in the mid-80's, the MR2 was one of the finest handling fun sports car gems available at a reasonable price. A friend of mine had a red one with black rag top. Riding in it was so much fun I took a dealership test ride. Both were white-knuckled experiences that took hours to wipe the smile off my face. The combination of top of the line handling performance, Toyota reliability and top down fun for thousands of dollars less than its competition made it second to none in my book. Unfortunately, I was starting a family at the time and it wasn't practical. This is why the market for pure 2 seaters is very limited - practicality. If you enjoy driving the twisties without slowing down, get yourself an old MR2 with a new set of rubber - you won't be disappointed. :shades:

A reporter is interested in talking with roadster fans who would like or dislike the idea of a smaller engine in the new BMW Z4. If you care to share your comments, please send an email, including your daytime contact info, to pr@edmunds.com no later than 5:00pm Pacific on Friday, August 12, 2011.

MODERATOR

Need help navigating? kirstie_h@edmunds.com - or send a private message by clicking on my name.

Hello! Im thinking of buying a used 2005 BMW Z4 w/ 42,000 miles on it, the carfax was clean but i havent own a bmw before much more a z4 i'm wondering at what point you started doing repairs on your z4 at how many miles? should i even consider buying a z4 w/ 42,000 miles on it? im thinking of driving it for two more years before i trade it in, but i def. dont want to spend money on repairs, just thought i'd ask owners and do my due diligence. Thank you so much!

BMW Z4's don't require the heavy hitting major service interval until 100K. Until 50K miles or 4 years - all maintenance including oil changes (except rotors, brake pads and tires) is free. As you must know, your 2005 is outside the free service BMW warranty by 2 years now.

Still, 42K is very low mileage. Probably the only thing the car should need (if not already done) is brake pads, rotors and tires - possibly an oil change. You don't have to go to BMW for these repairs. You can save from 10-50% off what the dealer's typically charge by finding a good mechanic. Get four good A A A rated 50K non-run flat all season tires off the internet for under $400. Balanced and mounted for $40 to $80 depending where you get them mounted. Be careful where because BMW rims scrap easily unless a touchless tire mounting system is used.

Next comes regular service. A Lube/Oil/Filter I recommend every 7,500 miles (ignore the 15,500 mileage counter for service - it doesn&#146;t include LOF). You may hear the car can go 15,500 miles between synthetic oil changes - it really depends on how you drive, but you're likely to experience valve or other problems as the car nears 70K-100K if you neglect regular LOF. An LOF costs $100 or $200 at most BMW dealerships. Four rotors and pads is going to cost you something like $800, but you can get it done for hundreds less if you know a good mechanic, a friend or do it yourself. Every 15K miles, the car needs a full service which run $200-$400 (depending where you go to have it done). The major service is required typically every 30K miles. This runs about $1,000 to $2,000.

After about 7 years, the head light cover gaskets dry out and take a set. If a bulb burns out, you need to replace either the gasket or the headlight cover that comes with a new gasket. Otherwise, you'll be replacing bulbs every 3-6 months as moisture keeps collecting in the headlight. You may also need a new battery. I replaced mine for around $140 and it's twice the battery that comes stock with Z4s.

There&#146;s a reason that BMW offers free service the first 50K or 4 years &#150; they are bloody expensive cars to maintain. I have put about 25K on my Z4 a year the last 6 years. I can tell you that the Honda Civic I drove for the 10 years prior cost me about a quarter of what this car does in maintenance. but at the same time &#150; this car is 20 times more fun to drive! (even more so as a daily commuter.)

Way I figure it, you only live this life once - you might as well enjoy it. Treat others well, but always be true to yourself. Good Luck.

Thank you so much for the advice! funny you mentioned that you use to own a honda, that's me right now, and i've been driving the same honda civic for the past 10 years w/ little to no repair expense. But i figured, i might as well go for the fun car before i start popping kids and have to buy the mommy SUV lol so i was torn between sticking w/ the new Honda Civic for around $18K or this BMW z4 w/ 42k miles for $16,999. Like i said, im only planning on enjoying it for two/three years tops averaging 10K per year (thats how much i drive now). Again, thanks so much! i really apreciate the insight!

Hi there, I bought a 2004 Z4/Sport mode 6-speed July 2012, with 48k on it, LOVING IT! Have done front brake pads, replacing rear tires today with non run flats, can't fathom the thought of replacing OEM run flats every 12-15k. We'll see how that goes when I pick it up tonight. This car is THE most fun I've had on four wheels, and I had a 3-series ragtop back a ways. Some mornings, I just drive right by the office and keep driving for a bit, so nice!

If you only drive it when the weather is nice with less than 5,000 miles a year on your sweet Z4, use the OEM run flats.

If this is your every day car or you are trek more than 10K a year, definitely go with non-RFTs. Advantage is they can cost half as much and last 2-4 times as long. The disadvantage is you may lose 2-10% of cornering grip (depending on temperature and dryness).

Unless you are rich or race with a sponsor, it's probably not in your interest to use RFTs.

RunFlat tires are not necessarily rapid wear tires. And the opposite is also not true - that Non-RunFlat tires are good wearing tires.

The wear properties of tires is independent of whether or not the tire is a RunFlat - as is the traction properties. (Although it is true that many RunFlats only come in high traction varieties, which also means they don't wear well.)

Yes, tire life and traction are determined by their ratings. The price anyone pays for the higher ratings is generally higher. Also, the price one pays for the Run Flat extra feature is generally higher than the same tire with the same ratings.

However and from my experience, the &#145;feel&#146; of the Run Flat tire for an equal rated non-Run Flat tire is different. It &#145;feels&#146; like the Run Flat tire affords better traction, but a stiffer ride over bumps. I don&#146;t have anything statistical or accelerometer ratings to support this. They are simply my observations.

Don&#146;t think we ever left the same page, but happy we are back on it again now.